1. Field of the Invention
The invention relates to a combination device comprising an input terminal to which a telephone line can be connected and on which the combination device can receive an input signal formed by a call signal made up of call signal pulses and, subsequently, an information signal or a fax signal, and comprising fax means adapted to process a received fax signal, and comprising internal telephone means adapted to process a received information signal and to supply a first activation signal for activating a receiving mode of the combination device, to which telephone means an information signal received in the receiving mode can be applied in order to process this signal, and comprising an output terminal via which external telephone means can be connected to the combination device, and comprising call signal processing means connected to the input terminal and arranged to receive an input signal in a standby mode of the combination device and adapted to detect call signal applied to the combination device before an information signal or before a fax signal, which call signal processing means include an electroacoustic transducer for producing an acoustic ringing signal after detection of a call signal pulse of the call signal and are adapted to supply a second activation signal after the occurrence of a given number of call signal pulses in order activate the receiving mode, and which are adapted to produce acoustic ringing signals by means of the electroacoustic transducer in the absence of fax signal detection information in the receiving mode, and comprising fax signal detection means arranged to receive an input signal in the receiving mode and adapted to supply the fax signal detection information when the input signal is a fax signal, and comprising first switching means arranged to receive an input signal from the input terminal in the receiving mode and adapted to supply an input signal from a first output terminal of the first fax means to the fax means when fax signal detection information occurs and to supply an input signal from a second output terminal of the first switching means to the internal telephone means in the absence of a fax signal detection information.
2. Description of the Related Art
Such a combination device of the type defined in the opening paragraph is commercially available from the Applicant under the type designation HFC 8 and is consequently known. In this known combination device both the internal telephone means and the fax means, which are accommodated in a common housing, have an electrical construction as known per se from the apparatuses when they are each accommodated in a separate housing, i.e. from a separate telephone set and a separate fax apparatus. In addition, the known combination device includes a fax switch, which in the present case includes the call signal processing means, the fax signal detection means and the first switching means. In the standby mode of the known combination device the fax switch connects the input terminal of the known combination device to the output terminal of the known combination device, which output terminal can be connected to external telephone means, which may be formed by a so-called cordless telephone. When an input signal formed by a call signal is applied to the input terminal of the combination device the call signal is detected by the call signal processing means of the combination device, a loudspeaker provided as an electroacoustic transducer of the combination device producing an acoustic ringing signal, and is also detected by a further call signal processing stage provided in the external telephone means, as a result of which a further acoustic ringing signal is produced by a further loudspeaker of the external telephone means. In this standby mode the user of the combination device can lift the receiver of the external telephone means or the receiver of the internal telephone means, which lifting is detected by the telephone exchange which is connected to the combination device via the telephone line, upon which a generator stage provided in the telephone exchange to generate the call signal terminates the supply of the call signal, after which the speech signal as an information signal or the fax signal from the other subscriber is supplied to the combination device via the telephone line as the input signal for the combination device.
When in the standby mode of the known combination device the call signal processing means has detected a given number of call signal pulses in the call signal it activates the receiving mode of the combination device, which is detected by the telephone exchange which in response thereto supplies a speech signal or a fax signal from the other subscriber to the input terminal of the combination device. As a result of the activation of the receiving mode the above-mentioned connection between the input terminal and the output terminal of the combination device established in the standby mode is interrupted. Subsequently, the fax signal detection means check whether the input signal is a fax signal. If the input signal is a fax signal the known fax switch connects the input terminal to the fax means, upon which the fax means produce a fax message corresponding to the received fax signal on a record carrier formed by a paper sheet. When the fax signal detection means do not detect a fax signal and the input signal is consequently a speech signal, the call signal processing means are adapted to again produce acoustic ringing signals by means of the loudspeaker. Unfortunately, the known combination device has the problem that in the receiving mode, when the fax signal detection means have not detected a fax signal and the input signal is consequently a speech signal, the external telephone means cannot produce an acoustic ringing signal and it is therefore not possible to answer a telephone call with the external telephone means.